Nah Thanos is nowhere near as powerful as Odin, he can't even harm him plus if anyone kills Odin it should be Surtur.

Yeah I know MCU Odin lost his eye from Laufey, but I'm under the impression that Odin didn't have the Odin Force at the time. I say this because he really didn't seem anymore powerful than Thor in the flash back scene of his Frost Giant battle.

I wouldn't say "nowhre near" Thor, is nowhere near as powerful as Odin.

Well, it could all be a part of Thanos' plan. What if Thanos knew he couldn't defeat Odin. Hence this attack on Earth, Thor needed to be there, so Odin uses this Dark Energy to get Thor there, greatly weakening him, so then Thanos can kill him?